Objective: To observe the difference of gene expressions of brain tissues during apoplectic episodes and those of normal brain in Wistar rats in order to study the pathological mechanism of apoplexy. Methods: A rat model of hypertension was established with the administration of cold stimulus and high salt intake as the environmental risk factors.Apoplexy occurred in the rats because of hypertension. Suppression subtractive hybridization(SSH) was used to identify and analyze the differential genes specifically expressed in cerebral tissues of stoke group and control rats. Results: A total of 226 genes out of the 228 were usable and analyzed. The average length of the 226 genes was (286.6±120.3) bp with a range from 50 bp to 619 bp. And 126 clones out of the 226 showed a sequence with significant identity to the known genes; 78 clones demonstrated homogenous sequences to the existing ESTs ofdbEST, but no one of the 78 showed sequence with identity to that of known genes; and remaining 22 were novel transrcipts exhibiting no similarity to any known sequences. All the clones which were highly homogenous to the known genes were categorized on the basis of their function. It was found that 26.5% of the mitochodrial genes in brain tissues underwent changes after apoplexy and the changes showed a twofold relationship of cause and effect. Conclusion: Environmental factors are able to induce changes of gene expression, which may increase the sensitivity to apoplectic stroke.